Life History Trait Plasticity and Adaptations to Stochastic Environmental Divergences: High Arctic Charr

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This project represents an interdisciplinary study to test the hypothesis that stochastic climate and habitat variation play a decisive role in the development of life history traits, adaptation mechanisms and population composition in Arctic charr (Salvelinus alpinus) in high Arctic freshwater systems. The study combines geophysical observations with ecological, retrospective and genetic studies. The circumpolar Arctic charr is ideal for the study of how environmental factors affect life history, population structure and diversity in fishes. Charr populations demonstrate a tremendous ecological plasticity and adaptations to harsh environments. Arctic charr is the only freshwater fish in the high Arctic and, as elsewhere, has a broad range of life-history strategies including anadromous, resident and landlocked populations. In lake systems with migrating charr, the population may consist of a mixture of parr, postsmolt and adult migratory individuals, as well as small-sized resident, large-sized resident and large formerly resident individuals transformed to anadromy. Determination of the effect of the environment upon phenotype, genotype and life history relies upon detailed information about environmental conditions, developmental rates, genetic information, migration rates and mortality in extreme conditions. In this study charr populations from lake systems from the Thule, Disko, Nuuk and Julianehaab, Greenland and Ellesmere Island, Canada areas will be compared. Charr in all systems experience highly stochastic environments. Whereas adaptive, genetic and behavioral mechanisms associated with migration are well known for salmonid fish at lower latitudes, knowledge about such mechanisms in anadromous charr inhabiting high latitude environments are still fragmentary. In general, mechanisms associated with seasonal events must be pre-adaptive. How such pre-adaptive mechanisms are timed with, and influenced by, the unpredictable physical conditions allowing for charr migration in high Arctic systems will be the main topic of this propject.